<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>v-on的基本使用</title>
</head>
<body>
    <div id="app">
        <h2>{{counter}}</h2>
        <button v-on:click="add()">+</button>
        <button @click="sub()">-</button>
    </div>
</body>
    <script src="../js/vue.js"></script>
    <script>
        const app = new Vue({
            el: '#app',
            data: {
              counter: 0,
            },
            methods: {
                sub() {
                    this.counter--;
                },
                add () {
                    this.counter++;
                }
            }
        })
    </script>
</html>